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We propose a scheme to deal with certain time-dependent non-Hermitian Hamiltonian operators $H(t)$ that generate a real phase in their time-evolution. This involves the use of invariant operators $I_{PH}(t)$ that are pseudo-Hermitian with…

Quantum Physics · Physics 2017-06-19 Boubakeur Khantoul , A. Bounames , M. Maamache

We study a time-dependent non-Hermitian extension of the Sch\"utte-Da~Provid\^encia spin-boson Hamiltonian with complex couplings. A time-dependent Dyson map containing a squeezing transformation maps the model, in an admissible bounded…

Quantum Physics · Physics 2026-05-20 Andreas Fring , Marta Reboiro

We propose time-dependent Darboux (supersymmetric) transformations that provide a scheme for the calculation of explicitly time-dependent solvable non-Hermitian partner Hamiltonians. Together with two Hermitian Hamilitonians the latter form…

Quantum Physics · Physics 2019-02-26 Julia Cen , Andreas Fring , Thomas Frith

The Dirac Hamiltonian in the (2+1) dimensional curved space-time has been studied with a metric for an expanding de Sitter space-time which is a two sphere. The spectrum and the exact solutions of the time dependent non-Hermitian and angle…

Mathematical Physics · Physics 2015-09-30 Ozlem Yeşiltaş

This study investigates pseudo-Hermitian quantum mechanics, where the Hamiltonian satisfies a modified Hermiticity condition. We extend the uncertainty relation for such systems, demonstrating its equivalence to the standard Hermitian case…

Quantum Physics · Physics 2025-08-11 Boubakeur Khantoul , Bilel Hamil , Amar Benchikha

A non-Hermitian operator may serve as the Hamiltonian for a unitary quantum system, if we can modify the Hilbert space of state vectors of the system so that it turns into a Hermitian operator. If this operator is time-dependent, the…

Quantum Physics · Physics 2018-09-12 Ali Mostafazadeh

The equivalence between the Schr\"odinger and Heisenberg representations is a cornerstone of quantum mechanics. However, this relationship remains unclear in the non-Hermitian regime, particularly when the Hamiltonian is time-dependent. In…

Quantum Physics · Physics 2025-11-18 Chia-Yi Ju , Adam Miranowicz , Jacob Barnett , Guang-Yin Chen , Franco Nori

The metric associated with a quasi-Hermitian Hamiltonian and its physical implications are scrutinised. Consequences of the non-uniqueness such as the question of the probability interpretation and the possible and forbidden choices of…

Quantum Physics · Physics 2007-10-31 H. B. Geyer , W. D. Heiss , F. G. Scholtz

I point out that if one defines the operator $U_R(t)$ as done by M. Znojil in his reply [arXiv:0711.0514v1] to my comment [arXiv:0711.0137v1] and also accepts the validity of the defining relation of $U_R(t)$ as given in his paper…

Quantum Physics · Physics 2007-11-08 Ali Mostafazadeh

The solutions of the time independent Schrodinger equation for non-Hermitian (NH) Hamiltonians have been extensively studied and calculated in many different fields of physics by using L^2 methods that originally have been developed for the…

Quantum Physics · Physics 2009-11-11 Ido Gilary , Avner Fleischer , Nimrod Moiseyev

In this work we intend to study a class of time-dependent quantum systems with non-Hermitian Hamiltonians, particularly those whose Hermitian counterpart are important for the comprehension of posed problems in quantum optics and quantum…

Quantum Physics · Physics 2007-05-23 A. de Souza Dutra , M. B. Hott , V. G. C. S dos Santos

In this work we address systems described by time-dependent non-Hermitian Hamiltonians under time-dependent Dyson maps. We shown that when starting from a given time-dependent non-Hermitian Hamiltonian which is not itself an observable, an…

Quantum Physics · Physics 2017-03-07 F. S. Luiz , M. A. de Ponte , M. H. Y. Moussa

For many quantum models an apparent non-Hermiticity of observables corresponds to their hidden Hermiticity in another, physical Hilbert space. For these models we show that the existence of observables which are manifestly time-dependent…

Quantum Physics · Physics 2008-10-08 Miloslav Znojil

We provide a reviewlike introduction into the quantum mechanical formalism related to non-Hermitian Hamiltonian systems with real eigenvalues. Starting with the time-independent framework we explain how to determine an appropriate domain of…

Quantum Physics · Physics 2015-06-26 Carla Figueira de Morisson Faria , Andreas Fring

In an amended version of non-Hermitian interaction picture we propose to work with the states $\psi(t)$ in a dyadic representation. The control of evolution via two conjugate Schr\"{o}diner equations then renders the usual necessity of the…

Quantum Physics · Physics 2023-06-29 Miloslav Znojil

We discuss the time evolution of physical finite dimensional systems which are modelled by non-hermitian Hamiltonians. We address both general non-hermitian Hamiltonians and pseudo-hermitian ones. We apply the theory of Krein Spaces to…

Mathematical Physics · Physics 2019-01-30 R. Ramirez , M. Reboiro

We consider some basic problems associated with quantum mechanics of systems having a time-dependent Hilbert space. We provide a consistent treatment of these systems and address the possibility of describing them in terms of a…

Quantum Physics · Physics 2024-09-24 Ali Mostafazadeh

A class of non-Hermitian quadratic su(2) Hamiltonians having an anti-linear symmetry is constructed. This is achieved by analysing the possible symmetries of such systems in terms of automorphisms of the algebra. In fact, different…

Quantum Physics · Physics 2011-06-15 Paulo E. G. Assis

Non-stationary version of unitary quantum mechanics formulated in non-Hermitian (or, more precisely, in hiddenly Hermitian) interaction-picture representation is illustrated via an elementary $N$ by $N$ matrix Hamiltonian $H(t)$ mimicking a…

Quantum Physics · Physics 2024-02-27 Miloslav Znojil

$\mathcal{PT}$-symmetric quantum mechanics has been considered an important theoretical framework for understanding physical phenomena in $\mathcal{PT}$-symmetric systems, with a number of $\mathcal{PT}$-symmetry related applications. This…

Quantum Physics · Physics 2019-12-25 Da-Jian Zhang , Qing-hai Wang , Jiangbin Gong